The powertrain of a vehicle refers to a group of components that generate and deliver power to the road surface to propel the vehicle along the road. In general, the powertrain includes a power source that generates or provides power, and a transmission that transmits the power to the drive wheels of the vehicle. In an electric vehicle, or a hybrid vehicle operating in the electric mode, one or more electric motors serve as the power source. In such vehicles, a battery provides power to drive the motors to produce torque. An inverter coupled to the motors directs current to the motors to produce torque in response to a torque request by a driver of the vehicle. The driver controls the position of the accelerator and brake pedals to request different amounts of torque from the motors. When the driver presses down on (or depresses) the accelerator pedal, a controller detects the position of the pedal and sends a signal to the motors to increase the torque produced. When the driver releases the accelerator pedal and/or presses down on the brake pedal, the controller sends a signal to the motors to decrease the torque produced.
The transmission transmits the rotational power produced by the motors to the drive wheels of the vehicle. The transmission includes components that convert the speed and torque produced by the motor to that desired by the vehicle. One form of a transmission includes one or more gearboxes that use gears to provide speed and torque conversions between the motors and the drive wheels. Typically, an input shaft inputs power from a motor to a gearbox and an output shaft outputs the power from the gearbox to a drive wheel. The gearboxes include gears that selectively engage or disengage to increase or decrease the speed/torque between the input and output shafts. Typically, a control unit of the powertrain initiates a gear shift in the transmission in response to driving conditions.
In current transmissions with multiple gearboxes, gear shifting is initiated in each gearbox simultaneously. Such simultaneous gear shifting may affect the performance of the vehicle in some cases. Embodiments of the current disclosure may address these limitations and/or other problems in the art.